Investigation on the Gas Jet Flow Performance Confined in Round Pipe
In this study, the round jet flow behavior arose by the confinement was investigated experimentally and numerically. The confinement characteristics based on multi-scale characterizations in the atmospheric gas jet flow, which generated from a circular symmetrical subsonic nozzle and flowed into a c...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Isfahan University of Technology
2021-01-01
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| Series: | Journal of Applied Fluid Mechanics |
| Subjects: | |
| Online Access: | http://jafmonline.net/JournalArchive/download?file_ID=55046&issue_ID=1012 |
| _version_ | 1831664451345973248 |
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| author | H. Zhang L. Jia L. S. Cui C. H. Li |
| author_facet | H. Zhang L. Jia L. S. Cui C. H. Li |
| author_sort | H. Zhang |
| collection | DOAJ |
| description | In this study, the round jet flow behavior arose by the confinement was investigated experimentally and numerically. The confinement characteristics based on multi-scale characterizations in the atmospheric gas jet flow, which generated from a circular symmetrical subsonic nozzle and flowed into a confined round pipe, was used to studied. The studied region near the nozzle possess really short axial length (within 12d), providing initial conditions and boundaries that affected the flow behaviors in this region. A wide range of inlet velocities (0.98 m/s~84.72 m/s) and confined space sizes (1~20) were involved for simulated and quantitative discussions. The velocity profile evolution was recorded by simulations and characterized by a laser Doppler anemometer (LDA) with a resolution of 0.01 m/s. The confinement characteristics were systematically presented to elucidate the performance under the studied confined conditions with different metrics, such as centerline velocity decay (VR), entrainment rate (MR), pressure coefficient (Cp) and length of recirculation region (LR). The results indicated that the recirculation fluid action mainly contributed to the promoted initial velocity profile evolution with the introduction of the confined space. Theoretically, the confined space could reduce the maximum absolute entrainment mass flux, initiating a peak at the center of the recirculation region, which was controlled by the inlet velocity and the confined space size collectively. The remarkable effect of confined space size further contributes to the confinement characteristics of gas jet flow, representing a shortened flow distance despite similar process as that by reducing the diameter ratio (dR). In some cases, because of the miniaturization of confined space size, the dispersion of initial velocity profile evolution was not significant displayed throughout the variable inlet velocity range, especially when the dR was less than 2. This study gives a new insight in the performance of jet flow confined in round pipe, and such knowledge will be helpful to provide great potential and reference to applied fluid mechanics. |
| first_indexed | 2024-12-19T19:16:37Z |
| format | Article |
| id | doaj.art-4dde670e73044e54b61f78aa1e5c8192 |
| institution | Directory Open Access Journal |
| issn | 1735-3572 |
| language | English |
| last_indexed | 2024-12-19T19:16:37Z |
| publishDate | 2021-01-01 |
| publisher | Isfahan University of Technology |
| record_format | Article |
| series | Journal of Applied Fluid Mechanics |
| spelling | doaj.art-4dde670e73044e54b61f78aa1e5c81922022-12-21T20:09:07ZengIsfahan University of TechnologyJournal of Applied Fluid Mechanics1735-35722021-01-01143669680.Investigation on the Gas Jet Flow Performance Confined in Round PipeH. Zhang0L. Jia1L. S. Cui2C. H. Li3Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, ChinaBeijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, ChinaNational Institute of Metrology, Beijing 100029, ChinaNational Institute of Metrology, Beijing 100029, ChinaIn this study, the round jet flow behavior arose by the confinement was investigated experimentally and numerically. The confinement characteristics based on multi-scale characterizations in the atmospheric gas jet flow, which generated from a circular symmetrical subsonic nozzle and flowed into a confined round pipe, was used to studied. The studied region near the nozzle possess really short axial length (within 12d), providing initial conditions and boundaries that affected the flow behaviors in this region. A wide range of inlet velocities (0.98 m/s~84.72 m/s) and confined space sizes (1~20) were involved for simulated and quantitative discussions. The velocity profile evolution was recorded by simulations and characterized by a laser Doppler anemometer (LDA) with a resolution of 0.01 m/s. The confinement characteristics were systematically presented to elucidate the performance under the studied confined conditions with different metrics, such as centerline velocity decay (VR), entrainment rate (MR), pressure coefficient (Cp) and length of recirculation region (LR). The results indicated that the recirculation fluid action mainly contributed to the promoted initial velocity profile evolution with the introduction of the confined space. Theoretically, the confined space could reduce the maximum absolute entrainment mass flux, initiating a peak at the center of the recirculation region, which was controlled by the inlet velocity and the confined space size collectively. The remarkable effect of confined space size further contributes to the confinement characteristics of gas jet flow, representing a shortened flow distance despite similar process as that by reducing the diameter ratio (dR). In some cases, because of the miniaturization of confined space size, the dispersion of initial velocity profile evolution was not significant displayed throughout the variable inlet velocity range, especially when the dR was less than 2. This study gives a new insight in the performance of jet flow confined in round pipe, and such knowledge will be helpful to provide great potential and reference to applied fluid mechanics.http://jafmonline.net/JournalArchive/download?file_ID=55046&issue_ID=1012confined jet; confined pipe; confinement characteristics; size effect. |
| spellingShingle | H. Zhang L. Jia L. S. Cui C. H. Li Investigation on the Gas Jet Flow Performance Confined in Round Pipe Journal of Applied Fluid Mechanics confined jet; confined pipe; confinement characteristics; size effect. |
| title | Investigation on the Gas Jet Flow Performance Confined in Round Pipe |
| title_full | Investigation on the Gas Jet Flow Performance Confined in Round Pipe |
| title_fullStr | Investigation on the Gas Jet Flow Performance Confined in Round Pipe |
| title_full_unstemmed | Investigation on the Gas Jet Flow Performance Confined in Round Pipe |
| title_short | Investigation on the Gas Jet Flow Performance Confined in Round Pipe |
| title_sort | investigation on the gas jet flow performance confined in round pipe |
| topic | confined jet; confined pipe; confinement characteristics; size effect. |
| url | http://jafmonline.net/JournalArchive/download?file_ID=55046&issue_ID=1012 |
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